In this tutorial, bonsai specialist Harry Harrington demonstrates how to use liquid cyanoacrylate (commonly known as superglue or crazy glue) to preserve and strengthen deadwood in bonsai trees. He explains why cyanoacrylates are superior to traditional wet‑rot hardeners, waxes, and other preservatives, offering both structural reinforcement and the ability to carve delicate designs. Harrington showcases three real‑world examples—a hawthorn semi‑cascade with a carved trunk‑chop wound, a shrub honeysuckle with exposed roots, and an old garden juniper with a rotted base—illustrating the challenges each presents and how superglue resolves them. Practical guidance covers optimal application conditions (temperatures above ~10 °C, dry exterior wood, avoiding gel glues), the absorption and curing process, layering until no further uptake, and techniques for cleaning glossy or cloudy residues using a wire brush or Dremel. He advises a 2–3‑month weathering period before final finishing and notes that common colouring agents (lime sulphur, ash) can be applied before or after preservation. The video concludes with a reflection on the benefits of cyanoacrylate and a link to a detailed article for further information.
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So this is a common hawthorn semi-cascade bonsai. The reason for showing you this tree is that it features a very prominent piece of carving that I carried out 2 years ago to hide a large flat trunk chop wound. Because of its position on the tree, it is important to me that the deadwood design does not deteriorate over time As this would simply leave an ugly black cavity. So to ensure that the deadwood does not and cannot break down, I've used cyanoacrylate to preserve it. Also known as crazy glue or super glue, cyanoacrylates not only preserve the wood, they give it great structural strength, enabling me to create a very delicate looking deadwood design. The strengthening of the wood is the fundamental reason I have moved on from using wet rot hardeners, wax, and other preservatives. Here's another example of using cyanoacrylates, a shrub honeysuckle, or Lonicera, with exposed roots on the Agari. Honeysuckle has wood that will break down after a few years, and with so much deadwood in the design, it's been very necessary to preserve and strengthen the wood with the cyanoacrylate. Again, it has also enabled me to carve a very detailed design, the spiraling design, into one of the jinns. So if we move on to the practicalities of applying this chemical on an old garden juniper that I recently acquired with a very wet, rotted base from growing in poor quality soil, it is important to try and use the glue when temperatures are above 10 degrees centigrade Or the glue does not travel into the wood as well. Ordinary super or crazy glue is literally dropped over the wood. Don't use the gel types of glue as they contain silicone and are too viscous to penetrate very deeply. The super glue is absorbed into the wood until it hits some moisture. Super glue doesn't start to set until it hits this moisture, at which point there is a chemical reaction that sets it rock hard, allowing deeper penetration rather than simply hardening the very top layer of wood. The very best time to apply the super glue is during the summer months when the exterior of the deadwood is very, very dry, but you may still have the wet rot within. Try to avoid runoff into the bark for cosmetic reasons, as equally avoid using as much so much that it runs into the soil. However, the super glue will set as soon as it hits moisture on the soil surface, and it is very unlikely to cause any real problems to the roots. Just use some common sense when applying it. One of the most difficult areas of rotting wood to cure on any tree is around the roots and underneath the soil surface. Because I am also carefully removing the old organic soil that has caused the rot in the first place, I'm taking the opportunity to cure that submerged wood as well. As setting of the glue takes minutes, it is not necessary to leave the roots exposed for very long. Notice how close to the roots I am comfortably able to use the super glue. The super glue will slowly sink into the wood. You can keep applying further layers of glue until no more is absorbed. These areas will be left with a shiny glossy surface, but this is easily brushed with a wire brush. Where there is a high moisture content at the surface of the root— the wood, or you apply the super glue in cool conditions under 10 degrees centigrade, you find that the glue dries with a cloudy white opaque appearance. Again, this is easily removed with a wire brush fitted to a Dremel or by hand. Where the wood has a slightly wet appearance after preservation, you can simply wait for the wood to weather naturally in the garden for 2 to 3 months. Lime sulphur, ash, or any other colouring agents that you typically use can be used before or after preservation using the super glue. I hope you've enjoyed this short video. I wish I had learned about the, the cyanoacrylate a long time ago, given the problems I've had in the past trying to preserve wood that ends up crumbling away. For further information, please see the article on my website that I've linked to below.
